Slab Leak Water Damage in Austin, TX Under-Slab Leaks Traced and Dried

What is actually leaking under there

Post-tension and conventional slabs both carry pressurized supply lines and gravity drain lines beneath or within them. A supply leak runs continuously at line pressure and produces the classic signs: a section of floor that feels warm on a hot-water line, the sound of water with every fixture closed, and a rising bill. A drain leak only leaks when something upstream is used, so it hides longer and shows up as a persistent damp area near a bathroom or kitchen wall. Distinguishing the two decides the repair method, because a supply line can often be rerouted overhead while a drain line generally has to be reached.

Hard water and the age of the pipe

Austin Water publishes system hardness averaging 93 parts per million as calcium carbonate, or 5.4 grains per gallon, with values reported as high as 126 ppm. A USGS guide places that upper figure in the hard band and identifies calcium and magnesium as the source of deposits inside piping. Mineral scale narrows the bore, changes flow velocity, and concentrates wear at bends and joints, which is one contributing factor in pinhole failures on older under-slab copper. Age, soil chemistry, and installation quality all play a part, so this is a reason to inspect rather than a diagnosis on its own. It does mean that one under-slab pinhole on a house of a certain vintage is a reason to look at the rest of the run.

Meter data now dates the leak

Austin Water's meter replacement program set out to install 250,000 new meters over four years beginning in 2021, and on those accounts consumption is collected and transmitted daily, with readings reaching the customer portal within about 24 hours. Customers can also set their own high-use and leak notifications. For a slab leak that is a real diagnostic tool, because a continuous overnight draw with the house asleep is the signature of a supply leak under concrete. The utility's own no-cost check still works too: read the meter, use no water for a few hours, and read it again.

Locating without opening the whole floor

The point of a proper locate is to break the smallest possible piece of concrete. Pressure isolation tells you whether the leak is on the hot side, the cold side, or a drain. Acoustic listening, tracer gas, and thermal imaging narrow the position, and readings across the floor establish the wet footprint that drying will have to address. Opening the slab at a guess costs more than the locate did, and it puts a hole in the floor that still has to be closed whether the leak was there or not. On a post-tension slab the tendon layout has to be respected, which is a reason the coring decision belongs to people who confirmed it rather than assumed it.

The wet part is bigger than the hole

Water in the fill under a slab wicks into the concrete, and concrete gives moisture up slowly. Flooring installed over it traps that moisture, which is why vinyl plank cups, laminate swells at the seams, and tile releases from the mortar bed after a leak that seemed small. Bottom plates, baseboard, and the lower few inches of drywall along the affected wall take water by wicking, not by splashing. The drying scope therefore covers the slab surface, the perimeter framing, and enough of the floor covering removed to let the concrete release moisture, all set by meter readings rather than by the size of the visible stain.

The repair choices and what they cost you in time

Spot repair breaks and patches the slab at the leak. Rerouting abandons the failed segment and runs new line through walls and ceiling, which avoids further concrete work but adds drywall repair. Repiping addresses a system with several failures rather than one. Each path changes the drying timeline, because concrete cannot begin releasing moisture until the water stops arriving. Ask for the plumber's locate documentation and the method chosen, and keep it with the mitigation file. On covered losses the carrier reads the cause, the repair, and the drying record as one story.

How the visit runs

Confirm the leak is isolated or repaired, then extract any standing water and lift flooring over the wet footprint under a documented scope. Meter the slab, the plates, and the drywall base, and record the affected square footage with photographs. Dehumidification is sized against the wet surface, and specialty drying is used where moisture is bound in concrete and hardwood rather than sitting on it. Readings are logged on each return visit until materials reach target, and the floor is not reinstalled on a slab that has not been verified dry, because a moisture-blocked flooring failure six weeks later is a second job nobody wants to pay for.